18981319536 has 120 divisors (see below), whose sum is σ = 56390680944. Its totient is φ = 5939619840.

The previous prime is 18981319531. The next prime is 18981319541. The reversal of 18981319536 is 63591318981.

18981319536 is a `hidden beast` number, since 1 + 8 + 98 + 1 + 3 + 19 + 536 = 666.

It is an interprime number because it is at equal distance from previous prime (18981319531) and next prime (18981319541).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18981319531) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 962091 + ... + 981621.

Almost surely, 2^18981319536 is an apocalyptic number.

18981319536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18981319536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28195340472).

18981319536 is an abundant number, since it is smaller than the sum of its proper divisors (37409361408).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18981319536 is a wasteful number, since it uses less digits than its factorization.

18981319536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19959 (or 19950 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 54.

The spelling of 18981319536 in words is "eighteen billion, nine hundred eighty-one million, three hundred nineteen thousand, five hundred thirty-six".